Remove unused import that conflicts with torch 2.9 (#5810)

Signed-off-by: Kyunggeun Lee <quic_kyunggeu@quicinc.com>
Co-authored-by: Kyunggeun Lee <quic_kyunggeu@quicinc.com>

Author: 2 people

TrainingExtensions/torch/src/python/aimet_torch/onnx_utils.py

@@ -47,7 +47,6 @@
 from enum import IntEnum
 import torch
 from torch import nn
-import torch.onnx.symbolic_caffe2
 import torchvision
 import onnx
 import yaml